<!doctype html> 
<html> 
<head> 
    <meta charset="utf-8"> 
    <title></title> 
</head>
<body>
<script type="text/javascript">
	
alert(null + null == false - 1 === false)
// 0 == -1 === false
//false === false
//null + null == false // true
//0 == false
//true == 1
//1 -1 = 0;
//true
//false 
//
</script>
</body>
</html>